Development of vulnerability indicators

3. Development of vulnerability indicators

The development of indicators to assess various dimensions of climate change is also a recent and emerging area of study. One of the most definitive discourses of such indicators comes from the Inter-governmental Panel on Climate Change Report (IPCC 2007), which examines the concept of exposure, sensitivity and adaptive capacity as the basis for the development of effective climate change indicators. Firstly, vulnerability is a function of exposure to direct (such as changes in temperature and rainfall average) and indirect (e.g. increased risk of natural hazards) impacts. Secondly, it is a function of sensitivity of the region to them. The sensitivity could be environmental (e.g. land use), human (e.g. social structure), and/or economic (e.g. income per capita). Finally, exposure is correlated with adaptive capacity and adaptation in the following manner; reductions in exposure vulnerability as arising from the realization of adaptive capacity can be viewed as adaptation (IPCC 2007).

Sea levels have risen at an average rate of 1.8 mm per year since 1961, and at a rate of 3.1 mm per year since 1993. The increase in the rate of sea level rise has been attributed to thermal expansion and the melting of glaciers and polar ice caps¹¹. Global sea levels are projected to rise at a greater rate in the 21^st century than during the period of 1961 to 2003. Projections of future sea level rise range from 0.18 to 0.59 meters (relative to the average for 1980-1999) by 2099. Changes in sea levels are of particular concern because of the concentration of human settlements in coastal zones and on islands¹². Figure 2 illustrates the change in global sea level from 1880 – 2000. Future changes in sea level are not expected to be geographically uniform; data from analyses of tide gauges and thermal expansion tend to show greater trends in sea level rise for the North Atlantic Ocean than for the Indian, Pacific, or South Atlantic Oceans (Bindoff et al., 2007). The IPCC Fourth Assessment Report finds that sea levels “are likely to continue to rise on average” around the small islands of the Caribbean Sea¹³.

Sea level rise could have adverse effect on different sectors and infrastructure along the coast with the most vulnerable sectors being coastal communities and coastal tourism infrastructure¹⁵. Climate variability and change, coupled with human-induced changes, may also affect ecosystems; for example mangroves and coral reefs which could result in additional consequences for fisheries and tourism¹⁶. Although the actual extent of the areas to be affected by sea level rise is unknown, it is evident that such rises in sea level could cause coastal erosion and extensive coastal inundation, which will lead to coastal habitat destruction, loss of property and lives. Sea level rise could increase the socio-economic and physical vulnerability of coastal cities and may cost up to 14 per cent of GDP in coastal countries (IPCC 2007b).

Sensitivity indicator was the number of hotels.

There is little consensus on how hurricane frequency will change over time with climate change, but some studies have suggested an increase in intense hurricane activity in the North Atlantic^17,18. Projections for changes in hurricane intensity are not available, so as a proxy we examined which elements of the tourism system have historically been more affected by hurricanes.

The Hurricane Center¹⁹ has mapped hurricane trajectories, including intensity, for the last 150 years. Hurricane tracks were mapped using average wind speeds for the period 1951 – 2012.

Sensitivity was looked at based on the presence of key infrastructure/accommodations.

Changes in air temperature

To determine vulnerability of the tourism system to air temperature, current and future scenarios were developed using data from the climate change vulnerability analysis of the Caribbean coast of Belize, Guatemala and Honduras²⁰.

The analysis considered changes in air temperature according to emissions scenarios B1 and A2, for the period 2070-2099. Exposure was measured according to the certainty that an increase of over 3°C will occur, according to the different scenarios modelled. Vulnerability categories are based on the IPCC methodology²¹.

Degree heating weeks (DHW): cumulative measure of the intensity and duration of thermal stress, measures the hotspot stress over a 12 week period. DHWs over 4 have been shown to cause significant coral bleaching. Values over 8 have caused widespread bleaching and some mortality. Two DHWs is equivalent to one week of HotSpot values at 2 deg C or two weeks of HotSpot values at 1 etc. (from NOAA Coral Reef Watch).